Here are some links to a few translations and papers on the Chanjing meditation manuals which are preserved in Chinese translation. Florin Deleanu gives a general overview of this group of texts in Mindfulness of Breathing in the Dhyāna Sūtras:

The term dhyāna sūtra represents a reconstruction of the Chinese chan jing, which appears in the titles of a certain group of texts as well as in the writings of Chinese Buddhists of the early 5th century AD as Sengrui, Huiyuan, and Huiguan.

This group represents treatises or manuals of meditation belonging to or, at least, partly drawing their inspiration from Sarvāstivāda tradition. We must not forget, however, that many of the dhyāna sūtras are, as it were, a common product of the Buddhist traditions from North-West India, Central Asia, and China. Although the basic material of these texts doubtlessly comes from Indian Buddhism, we must not exclude the possibility that they were compiled in Central Asia or that Buddhist monks from Central Asia, who in most of the cases were those who brought the dhyāna sūtras to China, had a more or less substantial influence on the final form of the scriptures in the process of translating them into Chinese. Kumārajīva would be perhaps the most eloquent example of this case.

Doctrinally, the dhyāna sūtras range from a basically orthodox Sarvāstivāda standpoint to a substantial compromise with Mahāyāna teachings and practices. In some cases, this compromise is so advanced that it is very difficult to make a distinction between such a text and a samādhi sūtra (sammei jing), which represents a purely Mahāyāna scripture....

Although the textual formation of many of these dhyāna sūtras remains a very complicated process, the original texts or, at least, much of the meditation practices and doctrines, especially those associated with Conservative Buddhism, can be traced back to the Kashmirian Yogācāra school belonging to the Sarvāstivāda tradition. Most of these meditation manuals were compiled or, at least, reflect the practice and theory of the Sarvāstivāda Yogācārins of the first four centuries of our era.

To date, the best English language translation of one of these texts is The Sūtra on the Concentration of Sitting Meditation, translated by Nobuyoshi Yamabe and Fumihiko Sueki (listed below). Please add any other relevant texts, translations, and studies.

Greene, Eric. Of Bones and Buddhas: Contemplation of the Corpse and its Connection to Meditations on Purity as Evidenced by 5th Century Chinese Meditation Manuals. M.A. Thesis. University of California, 2006.